once you've registered, you do NOT need to "re-add" yourself -
This is from the FTC website - http://www.consumer.ftc.gov/articles/0108-national-do-not-call-registry
"Will My Registration Expire?
How long does my phone number stay registered?
Telephone numbers on the registry will only be removed when they are disconnected and reassigned, or when the consumer chooses to remove a number from the registry."
Kathy- If you bothered to research before coming on here to complain about something you obviously know nothing about, life would be so much less stressful. The DNC list DOES work and DOES do what it is supposed to,,,,,for legit companies that follow the law. What exactly do you suggest that the govt. do when the majority of these calls from scammers, people calling from overseas or from groups that are happy to break the law and do whatever they want? Obviously there are thousands of them breaking the law and they know every little trick and scam including spoofing numbers so we can't figure out where they are. Quit whining about a legit agency doing what they are supposed to do. You're so dang smart, YOU figure out a way to stop them.
iPhone users can go to the Recent Calls section, pulling up this number's newly created contact card, and go to the bottom to block them. You can Google for the process specific to your phone if you don't have an iPhone.